Cutting plate for a processing tool and holding device for such a cutting plate

ABSTRACT

A cutting plate for a processing tool, particularly a milling tool, is connected to a holding device for such a cutting plate. The cutting plate has at least one blade ( 1 ) configured in a radially protruding manner on a central body ( 5 ) of the cutting plate. The central body ( 5 ) is provided with a coupling part for mounting the cutting plate on a frontal seat of a shaft-type holding device ( 15 ) which defines a longitudinal axis. The coupling part forms at least one driving surface transmitting an operating torque from the holding device ( 15 ) to the cutting plate. The cutting plate also includes a shaped part which forms a fixing device on the seat ( 17 ) of the holding device ( 15 ) in cooperation with an associated embodiment ( 35 ).

FIELD OF THE INVENTION

The present invention relates to a cutting plate for a processing tool,a milling tool in particular, having at least one cutting edgeconfigured to project radially from a central body of the cutting plate.This central body has, for the purpose of mounting the cutting plate ona frontal seat of a shaft-like holding device defining a longitudinalaxis, a coupling component forming at least one driving surface fortransferring operating torque from the holding device to the cuttingplate. A boring in the central body is concentric with the axis ofrotation and is designed to secure the cutting plate axially in the seatof the holding device.

BACKGROUND OF THE INVENTION

Cutting plates which, together with a shaft-like holding deviceconnected to a drive spindle or to a non-rotating machine support whichmay be controlled to execute adjustment movements, form a rotating ornon-rotating machine tool. DE 34 48 086 C2, for example, discloses atool of this kind for inside machining. Such tools are widely used formachining processes which must be executed with high precision. Toensure adherence to correspondingly narrow tolerances, it is extremelyimportant to achieve strict coordination of cutting plate and theholding device corresponding to it. In other words, care must be takento make certain that a particular holding device only mounts cuttingplates having bodies with coupling components adapted with precision tothe geometry of the seat on the holding device. Consequently, to ensureoptimal machining results, the user must take great care to ensure thatthe only cutting plates used with a given holding device are ones whichbelong to an associated type classification meeting the correspondingspecifications provided by the manufacturer for the cutting plate andthe holding device. Even if the user does pay careful attention to thispoint, the possibility nevertheless exists that cutting plates notprovided or intended for use with a particular holding device may bemounted on an inappropriate holding device.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a cutting plate forwhich it is ensured that only a desired optimal combination of thecutting plate and a holding device will be formed.

With the present invention, this object is attained by a cutting platehaving a structural part which forms a non-interchangeability mechanismin conjunction with an associated configuration on the seat of theholding device.

This structural part necessarily makes certain that the only cuttingplates which may be mounted on a given associated holding device areones with that specific structural part typifying the specification andforms part of the non-interchangeability mechanism.

In the case of cutting plates in which the coupling component has, ashas already been disclosed, carrier components can be in the form ofribs projecting axially from the components. The ribs extend radially onthe driving surface for the transfer of torque. The structural part forthe non-interchangeability mechanism may be configured on one of thoseribs.

For example, a recess provided in the form of a flattening of therespective rib may be provided as structural part of thenon-interchangeability mechanism.

A recess positioned on the cutting plate in an area between two ribs maybe provided alternatively as a structural part of thenon-interchangeability mechanism.

Another object of the present invention is to provide a holding devicefor cutting plates with a configuration provided on the seat for thecutting plate forming a non-interchangeability mechanism on the body ofthe cutting plate in conjunction with a structural part.

In one preferred exemplary embodiment, this configuration may be in theform of an axial projection on the seat for the cutting plate. Theprojection extends, when an associated cutting plate is mounted, into arecess made in the cutting plate body. A recess is provided on thecutting plate as a structural part of contact of thenon-interchangeability mechanism.

The axial height of the projection preferably is somewhat smaller thanthe depth of the recess in the associated cutting plate. The projection,which for example is in the form of an axially projecting pin on theseat of the holding device, on its outer end, does not form a part ofthe surface of the seat and the cutting plate.

If the recess provided for engagement of the pin on the body of thecutting plate is in the form of a pocket bore, this bore preferably isdimensioned so that clearance is also obtained between the side walls ofthe pin and the pocket bore. Accordingly, the pin may be seated in thepocket bore without coming in contact with the body of the cuttingplate.

Other objects, advantages and salient features of the present inventionwill become apparent from the following detailed description, which,taken in conjunction with the annexed drawings, discloses preferredembodiments of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring to the drawings which form a part of this disclosure:

FIG. 1 is a perspective view of a milling tool having a cutting platewith four cutting edges according to a first embodiment of the presentinvention;

FIG. 2 is an enlarged, partial and exploded perspective view of thefront end area of the milling tool of FIG. 1, the cutting plate beingshown raised from the seat of the holding device;

FIG. 3 is a top plan view of the seat of the holding device of themilling tool of FIG. 1 on a scale smaller than that of FIG. 2;

FIG. 4 is a bottom plan view of the cutting plate of the firstembodiment in the direction of the side of the cutting plate forming thecoupling component;

FIG. 5 is a side elevational view of the milling tool of FIG. 1 in asection taken along line V—V in FIG. 3;

FIG. 6 is an enlarged, partial and exploded perspective view of amilling tool according to a second embodiment of the present invention;

FIG. 7 is a bottom plan view of the cutting plate of the milling tool ofFIG. 6 viewed in the direction of the side of the cutting plate formingthe coupling component; and

FIG. 8 is a side elevational view of the milling of FIGS. 6 and 7 insection.

DETAILED DESCRIPTION OF THE INVENTION

In the first exemplary embodiment illustrated in FIGS. 1 to 5, arotating milling tool has a machining axis of rotation 9. The cuttingplate has four cutting edges 1 provided on the components 3 projectingradially from the body 5 of the cutting plate. The cutting edges aredisplaced through an angle of 90° relative to one other. The body 5 ofthe cutting plate has a central bore 7 concentric with the machiningaxis of rotation 9, and has a boring section in the form of a taperingsurface 11 (FIG. 2) widening toward the exterior. A fastening screw 13,shown only in FIG. 1, has a conical section fitting on the taperingsurface 11. The cutting plate may be screw-fastened by the screw at itsrear surface to a holding device 15 in the form of a milling cuttershaft. The holding device 15 has, on its frontal surface, a seat 17 forthe cutting plate. In the center of the seat, a bore 19 is concentricwith the machining axis of rotation 9, and is provided with internalthreading for the fastening screw 13. In its interior, the shaft of theholding device 15 has flow channels for delivery of coolants/lubricantswhich are discharged by way of apertures 21 distributed over thecircumference of the seat 17.

As shown particularly in FIG. 4, the body 5 of the cutting plate forms,on the side provided for mounting in the seat 17 of the holding device15, a coupling component 23 with a circular end face 25 extendingperpendicularly to the axis of rotation 9. Three ribs 27 extend axiallyfrom the plane of the end face 25, and enclose equal central anglesrelative to each other. These ribs 27 extend radially from the bore 7 tothe circumference of the end face 25. Each rib 27 forms, on one of itsside flanks, a driving surface for transfer of drive torque from theholding device 15 to the cutting plate. One of the ribs 27, in theexample illustrated in rib 27 positioned on the left in FIG. 4, has onits upper side a flattened part 29 forming on the upper surface of thisrib 27 a recess which adjoins the bore 7. The recess formed by theflattened part 29 forms a structured part which forms anon-interchangeability mechanism in conjunction with a correspondingconfiguration provided on the seat 17 of the holding device 15.

As is to be seen in FIGS. 2 and 3, a rib-like annular surface 31projects a short distance axially on the circumference of the seat 17 ofthe holding device 15. If the cutting plate is mounted on the seat 17 ofthe holding device 15, the end face 25 of the cutting plate is separatedby a short distance from the annular surface 31. As is shown the mostclearly in FIG. 2, grooves 33 in the frontal surface of the seat 17 areformed to complement ribs 27 on the coupling component 23 of the cuttingplate. These ribs are seated in these grooves when the cutting plate ispressed against the holding device 15 by the screw 13. Support of thecutting plate and transfer of torque resulting from contact of theflanks of the ribs 27 with associated wall areas of the grooves 33. Asmall amount of clearance remains, as has already been pointed out,between the circumferential annular surface 31 and the end face 25.

FIGS. 2 and 3 show a pin 35 extending axially from the bottom of one ofthe grooves 33. In FIG. 3, this one groove 33 is positioned on theright. As shown in FIG. 5, the pin 35 extends into the recess formed inthe body 5 of the cutting plate by the flattened part 29 of theassociated rib 27 when the cutting plate is mounted on the seat 17 ofthe holding device. The axially measured height of the pin 35 and depthof the rib 27 formed by the flattened part 29 are dimensioned so thatthe pin 35 ends with a small amount of clearance between it and theflattened part 29. Consequently, the end of the pin 35 does not form apart of the surface of contact of the body 5 of the cutting plate withthe seat 17 of the holding device 15. The mutual local and dimensionalassociation of the components on cutting plate and holding deviceforming the non-interchangeability mechanism, specifically, thestructural part on the cutting plate formed by the flattened part 29 andthe configuration of the seat 17 of the holding device 15 with a pin 35projecting in the direction of the flattened part 29, forces formationof a failsafe device preventing the mounting of a “wrong” cutting plateon a holding device which is provided and configured exclusively for useof special cutting plates.

Structural parts other than the flattened part 29 shown and theprojecting pin 35 could, of course, be provided on the holding device.Other configurations on the seat of the holding device forming thedesired non-interchangeability effect could, of course, be provided.

FIGS. 6 to 8 show a second exemplary embodiment with a modifiedconfiguration of the non-interchangeability mechanism. As in the firstexemplary embodiment, a pin 35 projecting from the seat 17 of theholding device 15 is provided as a component of thenon-interchangeability mechanism associated with the holding device 15.Unlike the example first described, however, the pin 35 does not extendfrom the bottom of one of the grooves 33, but rather is positioned onthe seat 17 in the area between two grooves 33. The recess provided formounting of the pin 35 on the body 5 of the cutting plate accordingly isnot provided as a flattened part of a rib 27, but is rather configuredas a pocket bore 39 positioned between two ribs 27 on the couplingcomponent 23.

As is seen in FIG. 8, the pin 35 and the pocket bore 39 are dimensionedwith respect both to their axial extent and their thickness or width sothat there is a gap on all sides between the surface of the pin 35 andthe surface of the inside of the pocket bore 39. As FIG. 8 shows, thepin 35 is introduced into the pocket bore 39 without coming into contactwith the body 5 of the cutting plate.

The present invention has been described with reference to the exampleof rotating milling tools. The present invention could also be appliedto a non-rotating tool, such as a tool having a cutting edge on thecutting plate for inside machining of a rotating workpiece.

While various embodiments have been chosen to illustrate the invention,it will be understood by those skilled in the art that various changesand modifications can be made therein without departing from the scopeof the invention as defined in the appended claims.

1. A cutting tool, comprising: a shaft holding device having a frontalseat with grooves therein; a cutting plate having a central body and atleast one cutting edge projecting radially from said central body; acoupling component defining a longitudinal axis, mounting said cuttingplate on said frontal seat of said holding device, having at least onedriving surface transferring operating torque from said holding deviceto said cutting plate and having three ribs with said driving surface,said ribs projecting axially from said central body, enclosing equalcentral angles relative to one another, extending radially and beingcomplementary to said grooves in said frontal seat; a bore in saidcutting plate concentric with said longitudinal axis for receiving ascrew to secure said cutting plate to said frontal seat of said holdingdevice; and a structural part on said cutting plate forming anon-interchangeability mechanism with an associated configuration onsaid frontal seat of said holding device.
 2. A cutting tool according toclaim 1 wherein one of said structural part and said associatedconfiguration comprises a recess extending in an axial direction.
 3. Acutting tool according to claim 1 wherein said structural part comprisesa recess formed by a flattened part of one of said ribs.
 4. A cuttingtool according to claim 1 wherein said structural part comprises arecess extending in an axial direction and being positioned between twoof said ribs.
 5. A cutting tool according to claim 1 wherein saidassociated configuration comprises an axial projection on said frontalseat, and said structural part comprises a recess receiving said axialprojection.
 6. A cutting tool according to claim 5 wherein said axialprojection has an axial extent less than an axial depth of said recess.7. A cutting tool according to claim 6 wherein said axial projectioncomprises a pin extending axially from said frontal seat parallel withsaid longitudinal axis.
 8. A cutting tool according to claim 7 whereinsaid pin has smaller axial length and thickness than said recessallowing said pin to be received in said recess without contacting saidcentral body.
 9. A cutting tool, comprising: a shaft holding devicehaving a frontal seat with grooves therein; a cutting plate having acentral body and at least one cutting edge projecting radially from saidcentral body; a coupling component defining a longitudinal axis,mounting said cutting plate on said frontal seat of said holding deviceand having at least one driving surface transferring operating torquefrom said holding device to said cutting plate; a bore in said cuttingplate concentric with said longitudinal axis for receiving a screw tosecure said cutting plate to said frontal seat of said holding device; astructural part on said cutting plate forming a non-interchangeabilitymechanism with an associated configuration on said frontal seat of saidholding device; and one of said structural part and said associatedconfiguration comprises a recess extending in an axial direction, andthe other of said structural part and said associated configurationcomprises an axial projection received in said recess.
 10. A cuttingtool according to claim 9 wherein said structural part comprises saidrecess, extends in an axial direction and is positioned between two ribsprojecting axially from said central body.
 11. A cutting tool accordingto claim 9 wherein said axial projection is on said frontal seat, andsaid recess is on said central body.
 12. A cutting tool according toclaim 9 wherein said axial projection has an axial extent less than anaxial depth of said recess.
 13. A cutting tool according to claim 9wherein said axial projection comprises a pin extending axially parallelwith said longitudinal axis.
 14. A cutting tool according to claim 13wherein said pin has smaller axial length and thickness than said recessallowing said pin to be received in said recess without contactingsurfaces defining said recess.